First on-console run: the Identity suite failed with the device ID reading
00 00 00 10 instead of 04 02 02 00. Bit analysis shows that is an EXACT
match for the correct stream delayed by 22 bits -- the device answers
correctly, just too late for a 32-clock window to catch more than its first
set bit. Not corruption, and not a broken link: response latency.
At EXI index 5 (~27 MHz) 22 bit-times is ~815 ns, which is about what the CDC
chain costs (rx AsyncFIFO capture->exi, register-file decode, tx AsyncFIFO
exi->capture, SPI engine) at a 24 MHz exi clock. The design expects the GC to
hold the clock idle between the header write and the data read so the register
file can prefetch the response; libogc's inter-call overhead alone is not
enough at full speed.
Adds bba_gap_us (default 16 us, busy-waited with CS asserted since we hold the
EXI lock) and a Gap sweep test that reports the minimum clean gap at the
current speed -- which measures the latency rather than guessing at it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
gc_bba_test/ builds a .dol that drives the adapter over raw EXI from the
console and reports pass/fail per test on the TV, navigable with the pad.
Uses libogc's EXI API against EXI0:2 (Serial Port 1) rather than its bba
network driver: driving the register file directly gives each check its own
verdict, so a failure points at a specific register instead of at
'networking'. Six suites - identity, registers, reset/control, EXI link
integrity (including an EXI clock-index sweep), ethernet TX/RX, SPRAM/DMA
streaming.
Encodes the hardware lessons from bring-up so the app cannot mislead:
* the device ID is a one-shot cleared by the first NCRA reset, so it is
reported SKIP on a re-run rather than FAIL
* TI means the frame reached the W5100, NOT the wire - the TX test says so
* register reads clock exactly the requested length (over-clocking
desynchronises the next transaction)
* TXDATA is written one byte per transaction (eff_addr auto-increments)
.devcontainer/Dockerfile gains the devkitPro gamecube-dev group. devkitPro
publishes no .deb on GitHub, so this uses their installer script against
apt.devkitpro.org -- which is 403 from inside the running container's egress
but reachable from a host-side docker build. Rebuild the container to get it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Roflin